Disc drives are used for data storage in modern electronic products ranging from digital cameras to computers and network systems. Typically, a disc drive includes at least one disc with a recording surface rotated at a constant speed by a spindle motor assembly and an actuator assembly positionably controlled by a servo system. The actuator assembly supports a read/write head that writes data to and reads data from the recording surface.
One type of data recorded to and read from the information tracks is servo data. Servo data includes a physical track identification portion (also referred to as a servo track number or physical track number) written to the recording surface to define each specific physical track of a number of physical tracks written on the recording surface, and servo bursts that indicate fine position within a physical track. Servo data is recorded on the recording surface at servo sector locations. A servo track writer is traditionally used in writing a predetermined number of servo sectors to each recording surface during the manufacturing process. As explained above, the data in the servo sectors are used by the servo system for controlling the position of the read/write head relative to the recording surface during disc drive operations.
Typically, servo track writing is done after the disc drive is assembled. Once assembled, the servo track writer uses the disc drive read/write heads to record the servo track data. A recent disc drive servo track writing technology known as Multi-Disc Writing (MDW) writes at least two discs at a time that are then assembled in the disc drive.